Link model for multi-prefix packet system bearer

ABSTRACT

A second internet protocol network is logically connected to a packet data network connection provided between a user equipment and a first internet protocol network over a radio access network, the second internet protocol network located on a data path from the first internet protocol network to the user equipment. The first internet protocol network represents the highest level internet protocol point of attachment to the packet data network connection. Router advertisements are sent from the second internet protocol network to the user equipment over the radio access network via the packet data network connection.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to methods and apparatuses for providing alink model for a multi-prefix packet system bearer, e.g. an evolvedpacket system bearer.

2. Related Background Art

The following meanings for the abbreviations used in this specificationapply:

-   3GPP Bearer=a dedicated point to point connection for a UE-   3GPP=third generation partnership project-   ANDSF=access network discovery and selection function-   API=application programming interface-   APN=access point name-   DSMIPv6=dual stack mobile IPv6-   eNB=evolved nodeB-   EPS=evolved packet system-   GGSN=gateway GPRS support node-   GPRS=general packet radio service-   GRE=generic routing encapsulation-   GTP=GPRS tunneling protocol-   HeNB=home eNodeB-   IAP=internet access point-   IPv6=internet protocol version 6-   ISP=internet service provider-   L1=Layer 1=physical layer-   Link=interface at link layer (layer 2)-   L-GW=local gateway-   LIPA=local IP access-   MAPCON=multi access PDN connectivity-   MME=mobility management entity-   NIC=network interface connection at physical layer-   OPIIS=operator policies for IP interface selection-   OS=operating system-   PDN=packet data network-   PDP=packet data protocol-   PGW=P-GW=packet data gateway-   PMIPv6=proxy mobile IPv6-   PPP=point to point protocol-   RA=routing advertisement-   RAT=radio access technology-   SGW=S-GW=serving gateway-   SIPTO=selected IP traffic offload-   UE=user equipment-   ULA=unique local address-   USB=universal serial bus

3GPP Rel-8 has introduced dual-stack for EPS, and 3GPP Rel-9 hassupported dual-stack correspondingly for GPRS bearers. That is, PDN/PDPtype has been extended to IPv4v6, i.e., both IPv4 and IPv6 addresses areavailable to a UE.

Based on agreed IP addressing principle, exactly one IPv4 address andexactly one IPv6 prefix can be assigned to the UE (excluding link scopedprefix) per a PDN connection/PDP context.

New features beyond 3GPP Rel-9 like LI PA, SIPTO, MAPCON, OPIIS andequivalent mechanisms have shown that there is a need for more IPv6prefixes per bearer, for example to have a separate prefix for usertraffic “offloading” purposes.

The current 3GPP bearer model is proprietary and tailored for 3GPPterminals by assuming that end-users will use mobile operator providedpacket switched services.

However, smart phones are coming into the market that use ordinaryinternet services, and their operating systems implement their IP stackand network interfaces at link layer according to generic IP networkingprinciples. Thus, interworking between applications using socket basedIP stack in a smart phone OS and a 3G modem using bearers is quitecomplex.

A proprietary 3GPP bearer model that is limited to one IPv6 prefix perPDN is becoming problematic especially when IPv6 will be applied inlarger scale.

IPv6 is by design a multi-addressed and -prefix architecture, in whichan interface must have a link scoped prefix and then may have zero ormore prefixes of wider scope (ULAs, globals, . . . ). ISPs with complexcontent & service provisioning structure and access infrastructuresharing settlements make use thereof.

The 3GPP bearer model comprises an “old” point-to-point link model usedsince GPRS, in which the link is between a UE and a PGW/GGSN, and a“new” point-to-point link model used with PMIPv6, in which the link isbetween a UE and an SGW but an IPv6 prefix/IPv4 address is stilltopologically anchored to a PGW.

Since GPRS times 3GPP compliant host OSes have abstracted a PDPconnection as a dial-up “PPP-like” interface. Modern host OSes wish toabstract everything as IEEE802 type interface. This results in notworking combinations due to false assumptions made at both end host andnetwork side regarding link model and addressing.

A 3GPP solution for multiple prefixes is to establish a new defaultbearer (PDN connection) each time a new prefix is needed in the UE.However, this causes unnecessary overhead.

According to patent application US 2011/110378 A1 “Method And ApparatusFor Communications Traffic Breakout”, published on May 12, 2011, morethan one address per PDN connection/PDP context is used in order tooffload local breakout traffic in a “middle-box” on the data path byusing source address lookup (IP address, Ethernet address, or the like).

According to these applications, the current 3GPP bearer model ischanged to support multiple addresses per PDN connection.

SUMMARY OF THE INVENTION

Methods and apparatuses are proposed that overcome the above drawbacks.In particular, methods and apparatuses are proposed that provide for alink model for a multi-prefix packet system bearer, e.g. a multi-prefixEPS bearer.

These methods and apparatuses are defined in the appended claims. Theinvention may also be implemented by a computer program product.

According to an embodiment, an IP link model for a multi-homed link thatis passing via multiple network elements is provided.

Smooth interworking between applications using a socket based IP stackin a smart phone OS and a 3G modem using bearers can be achieved withthis link model.

The above and still further objects, features and advantages of theinvention will become more apparent upon referring to the descriptionand the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic block diagram illustrating a structure ofcontrol units for entities of a link model, according to an embodimentof the invention.

FIG. 2 shows a diagram illustrating a multi-homed link model for on PDNconnection according to an embodiment of the invention.

FIG. 3 shows a diagram illustrating a multi-homed link model as seen byan end host, according to an embodiment of the invention.

FIG. 4 shows a diagram illustrating a multi-homed link model as seen bythe end host, according to another embodiment of the invention.

FIG. 5 shows a diagram illustrating a shared prefix model for multipleUEs according to an embodiment of the invention.

FIG. 6 shows flowcharts illustrating methods performed by entities of alink model according to an embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following, examples and embodiments of the present invention aredescribed with reference to the drawings.

As a preliminary matter before exploring details of variousimplementations, reference is made to FIG. 1 for illustrating asimplified block diagram of various electronic devices that are suitablefor use in practicing the exemplary embodiments of this invention.

A control unit 10, which may be part of e.g. a laptop PC and mayfunction as an end host, comprises processing resources 11, memoryresources 12 and interfaces 13 which are interconnected by a link 14.The memory resources 12 may store a program that is executed by theprocessing resources 11. The interfaces 13 may comprise a NIC L1interface. The control unit 10 is connected to a control unit 20 via theinterfaces 13 over a link 15, e.g. USB.

The control unit 20, which may be part of a 3GPP terminal/modem (alsoreferred to as UE in the following), comprises processing resources 21,memory resources 22 and interfaces 23 which are interconnected by a link24. The memory resources 22 may store a program that is executed by theprocessing resources 21. The interfaces 23 may comprise a NIC L1interface and a 3GPP radio interface. The control unit 20 is connectedto the control unit 10 via the interfaces 23 over the link 15, and isconnected to a control unit 30 via the interfaces 23 over a radio link25.

The control unit 30, which may be part of a (H)eNB/L-GW of acommunications network system, comprises processing resources 31, memoryresources 32 and interfaces 33 which are interconnected by a link 34.The memory resources 32 may store a program that is executed by theprocessing resources 31. The interfaces 33 may comprise a NIC L1interface, a 3GPP radio interface and an S1 interface. The control unit30 is connected to the control unit 20 via the interfaces 33 over theradio link 25, to a control unit 40 via the interfaces 33 over a link 35and to a network (not shown) via the interfaces 33 over a link 45.

The control unit 40, which may be part of an S-GW of the communicationsnetwork system, comprises processing resources 41, memory resources 42and interfaces 43 which are interconnected by a link 44. The memoryresources 42 may store a program that is executed by the processingresources 41. The interfaces 43 may comprise a NIC L1 interface, an S1interface and an S5 interface. The control unit 40 is connected to thecontrol unit 30 via the interfaces 43 over the link 35, to a controlunit 50 via the interfaces 43 over a link 55 and to a network (notshown) via the interfaces 43 over a link 65.

The control unit 50, which may be part of a P-GW/GGSN of thecommunications network system, comprises processing resources 51, memoryresources 52 and interfaces 53 which are interconnected by a link 54.The memory resources 52 may store a program that is executed by theprocessing resources 51. The interfaces 53 may comprise a NIC L1interface and an S5 interface. The control unit 50 is connected to thecontrol unit 40 via the interfaces 53 over the link 55 and to a network(not shown) via the interfaces 53 over a link 75.

The terms “connected,” “coupled,” or any variant thereof, mean anyconnection or coupling, either direct or indirect, between two or moreelements, and may encompass the presence of one or more intermediateelements between two elements that are “connected” or “coupled”together. The coupling or connection between the elements can bephysical, logical, or a combination thereof. As employed herein twoelements may be considered to be “connected” or “coupled” together bythe use of one or more wires, cables and printed electrical connections,as well as by the use of electromagnetic energy, such as electromagneticenergy having wavelengths in the radio frequency region, the microwaveregion and the optical (both visible and invisible) region, asnon-limiting examples.

In general, the exemplary embodiments of this invention may beimplemented by computer software stored in the memory resources andexecutable by the corresponding processing resources, or by hardware, orby a combination of software and/or firmware and hardware in any or allof the devices shown.

The memory resources may be of any type suitable to the local technicalenvironment and may be implemented using any suitable data storagetechnology, such as semiconductor-based memory devices, magnetic memorydevices and systems, optical memory devices and systems, fixed memoryand removable memory. The processing resources may be of any typesuitable to the local technical environment, and may include one or moreof general purpose computers, special purpose computers,microprocessors, digital signal processors (DSPs) and processors basedon a multi-core processor architecture, as non-limiting examples.

As described in the following, one PDN connection is capable to handlemultiple different IPv6 prefixes. In other words, multiple APNs are notused, multiple interfaces (that multiple PDN connections usually imply)on UE side can be avoided, and end host OS default address selectiontakes care of addressing complexity, i.e. avoids 3GPP specific solutionsthat rely on traditional control model of the end hosts like ANDSFrouting policies or DSMIPv6 (S2c) traffic selectors.

According to an embodiment, a multi-homed link model for a one PDNconnection (or APN) that is passing via multiple network elements isproposed in which a P-GW/GGSN provides a “default” IP point ofattachment and intermediate local IPv6 networks on a data-path to a UEare connected logically to the same logical link by using physicalnetwork interfaces at S-GW and L-GW or (H)eNB nodes that are located atthese local IP networks and established tunnels (e.g. GTP or GRE) thatare associated to EPS bearer services within a PDN connection.

This logical link allows emulation of a multi-homed link so that a UE isable to receive router advertisements from multiple IPv6 networks andconfigure IPv6 addresses for different services within the same PDNconnection in a manner that is friendly to modern operating systems insmart phones.

Router advertisements from intermediate local IP networks are notadvertised to upper networks in the IP network topology within thislogical link, i.e. only the UE will receive a router advertisement fromall the IP networks connected to this logical link separately. Forexample, if the UE sees three networks, it will receive routeradvertisements from three different sources. One router advertisementcan contain zero or more prefixes (zero for the case when unnumberedlink model has to be supported). Furthermore, the prefix management isnot centralized. Rather, each network function sourcing a routeradvertisement is responsible for its own IPv6 prefix space and havingtopologically correct IP routing in place.

FIG. 2 illustrates a detailed multi-homed link model for a one PDNconnection.

A UE (3GPP Terminal/Modem) receives combined router advertisements (RAPGW+RA SIPTO+RA LIPA in FIG. 2) from each SGi interface at P-GW, S-GWand L-GW.

A network interface driver software in the 3GPP Terminal/Modem emulatesan IETF multi-homing compliant interface/link towards a modern operatingsystem in a smart phone or a personal computer as shown in FIG. 2. Each“access” shows up as a next-hop router to the personal computer as endhost. On a bearer level, “PGW access/link” gets mapped to a defaultbearer. Other “accesses/links” get mapped to dedicated bearers.

As shown in FIG. 2, networks are logically connected to a PDN connectionprovided between the 3GPP terminal/modem and the P-GW by using NIC L1and SGi interfaces at the S-GW and L-GW or (H)eNB nodes. The NIC L1 andSGi interfaces at the P-GW also connect to a network and this access ismapped to the default bearer transmitted between the P-GW and the S-GWover S5 interface. A session manager in an MME manages sessions in theS-GW and the P-GW.

The S-GW access is mapped to a dedicated bearer SIPTO transmitted overS1 interface between the S-GW and the L-GW/(H)eNB. The L-GW access ismapped to a dedicated bearer. The default and dedicated bearers aremapped to radio access bearers E-RAB 1, E-RAB 2 and E-RAB 3 by aconnection manager at the (H)eNB. The connection manager is connected tothe session manager over an S1AP interface. The default and dedicatedbearers are transmitted via a 3GPP radio stack managed by the connectionmanager over a 3GPP radio interface between the (H)eNB and the 3GPPterminal/modem.

A connection manager at the 3GPP terminal/modem maps the transmitteddefault and dedicated bearers to default and virtual IAPs at IPaddresses 1, 2 and 3, which are assigned for corresponding IAPs usingadvertised prefixes. As mentioned above, the network interface driver SW(3GPP compliant API) emulates the IETF multi-homing interface/linktowards the laptop PC, i.e. performs network abstraction. Data packetsare transmitted between the 3GPP terminal/modem and the laptop PC viaNIC L1 interfaces, for example over USB.

The OS running at the laptop PC takes care of addressing complexityusing the IETF multi-homing compliant interface/link and IP stack.

Referring again to FIG. 1, the laptop PC may contain the control unit 10and connect over the link 15 to the 3GPP terminal/modem containing thecontrol unit 20. The 3GPP terminal/modem may connect to the (H)eNB/L-GWcontaining the control unit 30 over the link 25. The (H)eNB/L-GW mayconnect to the S-GW containing the control unit 40 over the link 35. Andthe S-GW may connect to the P-GW containing the control unit 50 over thelink 55. The (H)eNB/L-GW may connect to a network over the link 45, theS-GW may connect to a network over the link 65, and the P-GW may connectto a network over the link 75.

FIGS. 3 and 4 illustrate how the end host sees a multi-homed PDNconnection. Each “route” or “access” is seen as a next-hop router on asingle shared link (Ethernet like) that the end host sees. Prefixes onthis shared link advertised by each router (SGi interface) are handledas off-link prefixes (all prefixes configured on these links must havethe L-bit set 0 with an exception of “LIPA link” whose prefix managementis outside mobile operator's control), meaning all packets are alwayssent to a correct next-hop router instead of trying to communicatedirectly with other hosts on the link. In case of LIPA-type access theprefixes may be on link (i.e. L-bit is set). In order the IPv6addressing to work properly, then all nodes using LIPA prefixes arelogically on the same level as each next-hop router the UE sees. Thisalso implies that possible multicast traffic originated from nodes fromthe “LIPA-link” should be sent to other routers on the virtual link aswell and multicast traffic originating from other “links” shall be sentto LIPA addressed nodes as well.

FIG. 3 illustrates modelling multi-homing as a number of distinctrouters to the end host by tunnelling multiple EPS bearers via a singlebase station. A UE with single radio may request the communicationsnetwork system to establish one default EPS bearer and one or morededicated EPS bearers that are associated to a single PDN connection.According to FIG. 3, multiple EPS bearers over a single radio-link/basestation can be used to connect distinct routers and forming a virtualmulti-homed network to the UE.

FIG. 4 illustrates modelling multi-homing as a number of distinctrouters to the end host by tunnelling multiple EPS bearers via amultiple radio links/base stations. A UE with multi-radio capability mayrequest the communications network system to establish EPS bearers byusing multiple radio link connections that are associated to a singlePDN connection. According to FIG. 4, multiple EPS bearers over multipleradio-links/base stations can be used to connect distinct routers andforming a virtual multi-homed network to the UE. The used radio linkconnections may use the same 3GPP RAT on different frequency bands, or acombination of 3GPP and non-3GPP RATs e.g. HSPA+LTE+WLAN.

It is also possible to have a common shared prefix for hosts attachingto one of the routers, e.g. not having a unique prefix for each end hostserved by one of the routers. This also changes the 3GPP bearer and PDNconnection model. Conventionally, shared prefixes are no supported.Still due to an “off-link” property of the prefixes no host attached tothe same router directly sees each other initially. They can also bemade always communicate via the router if IPv6 neighbour discoveryprotocol redirect messages are not supported by the router. This kind oflink model behaviour is important to make maximum reuse of existingradio technologies underneath (that eventually are point to point linksbetween the UE and the gateway router). Shared prefix model does notgenerally work too well with multiple interfaces. However, multipleprefixes are still alright. FIG. 5 shows a diagram illustrating thisapproach.

FIG. 5 shows a shared prefix model for multiple UEs. A group of P2Pradio bearers is abstracted at the P-GW as a single multicast/broadcastcapable link. The P-GW acts as an “MLD snooping WLAN switch”.

As mentioned above, the P-GW and its SGi interface provide the highestlevel IP point of attachment to a PDN connection seen in the UE and thecommunications network system. This link at the P-GW can naturally be amulti-homed link advertising multiple prefixes e.g. for differentservices. It is proposed to change the 3GPP bearer model so that the UE(3GPP terminal/modem) and the P-GW are allowed to associate multipleIPv6 prefixes to the EPS bearer(s) of a PDN connection.

In particular, the P-GW routes router advertisements at the P-GW (RAPGW, cf. FIG. 2) to the default EPS bearer. The UE (3GPP terminal/modem)passes router advertisements to the modern OS host (laptop PC in FIG. 2,but may be a smart phone as well) that may assign zero or more IPv6prefixes based on the received RAs and need at application layer.

3GPP based bearer management signaling/procedures can be used toestablish this enhanced default EPS bearer service between the UE andthe P-GW.

The S-GW and its physical network interface NIC L1 (network interfaceconnection at layer 1) is connected to a local IP network being situatedat the edge to RAN and it may provide e.g. offload routing for SIPTOtraffic.

It is proposed that the SGi interface at the S-GW is connected logicallyto the same link seen in the UE.

The S-GW is allowed to associate zero to more IPv6 prefixes to either adedicated EPS bearer (as shown in FIG. 2) or a default EPS bearer of aPDN connection. The S-GW routes router advertisements at the S-GW (RASIPTO, cf. FIG. 2) to a dedicated EPS bearer service to the UE ondata-path S-GW—(H)eNB—UE. RAs at S-GW are not sent to upper P-GW node.The S-GW routes user SIPTO traffic (IPv6 prefix from the SGi at theS-GW) to/from a local network at the S-GW.

The L-GW and its physical network interface NIC L1 is connected to alocal IP network e.g. at Home, Office, Corporate or Enterprise Networkand is used to obtain LIPA (Local IP Access) or SIPTO@Local Networkservice. The L-GW may be co-located in the (H)eNB as shown in FIG. 2 orimplemented as a stand-alone L-GW.

It is proposed that the SGi interface at the L-GW is connected logicallyto the same router link seen in the UE. However, the UE is on the otherside of the router than the SGi connected to the L-GW.

The L-GW is allowed to associate zero to more IPv6 prefixes to either adedicated EPS bearer as shown in FIG. 2 or a default EPS bearer of a PDNconnection. The L-GW routes RAs at the L-GW (RA LIPA, cf. FIG. 2) to adedicated EPS bearer service to the UE on data-path L-GW—(H)eNB—UE. RAsat L-GW are not sent to upper S-GW and P-GW nodes. The L-GW route userLIPA traffic (IPv6 prefix from the SGi at the L-GW) to/from a localnetwork at the L-GW.

The (H)eNB with its physical network interface may provide a simplebridging function to a local IP network without necessitatingimplementation of a co-located L-GW so that the local IP network becomesconnected to the same logical link associated to a PDN connection.

FIG. 6 shows flowcharts illustrating processes performed at the controlunits 20, 30, 40 and 50.

The control units 30, 40 may perform the functions of the L-GW/(H)eNBand S-GW, using their processing resources, memory resources andinterfaces, respectively.

In step S101, the control unit 30, 40 referred to as “second internetprotocol network” is logically connected to a packet data networkconnection provided between a user equipment (control unit 20) and afirst internet protocol network (control unit 50) over a radio accessnetwork. The second internet protocol network is located on a data pathfrom the first internet protocol network to the user equipment, whereinthe first internet protocol network represents the highest levelinternet protocol point of attachment to the packet data networkconnection.

In step S102, router advertisements are sent from the second internetprotocol network to the user equipment over the radio access network viathe packet data network connection.

The second internet protocol network may be connected to the packet datanetwork connection by means of a physical network interface (e.g. SGi)located at the second internet protocol network and establishing tunnelsassociated with bearer services, e.g. EPS bearer services.

An access of the second internet protocol network within said packetdata network connection may be mapped to a dedicated bearer and routeradvertisements at the second internet protocol network may be routed tothe dedicated bearer.

In step S201, the packet data network connection between the userequipment and the first internet protocol network is established overthe radio access network.

In step S202, an access of the first internet protocol network withinsaid packet data network connection is mapped to a default bearer.

In step S203, router advertisements at the first internet protocolnetwork are routed to the default bearer.

In step S204, the default bearer associated with the first internetprotocol network and a dedicated bearer associated with each of secondinternet protocol networks logically connected to the packet datanetwork connection are provided to the user equipment.

The default bearer and the dedicated bearer may be provided over asingle radio link between the user equipment and the radio accessnetwork, as shown e.g. in FIG. 3.

The default bearer and the dedicated bearer may be provided to the userequipment over multiple radio links between the user equipment and theradio access network, as e.g. shown in FIG. 4.

The first and second internet protocol networks may provide their owninternet protocol prefix space.

n internet protocol prefixes may be assigned either to the dedicatedbearer or the default bearer, wherein n is an integer equal to orgreater than zero.

A prefix advertised by the first and second internet protocol networksmay be set based on their level internet protocol point of attachment tothe packet data network connection.

A common shared prefix may be set for each end host served by thefirst/second internet protocol network, as shown e.g. in FIG. 5.

In step S301, the packet data network connection is established betweenthe user equipment and the first internet protocol network over theradio access network.

In step S302, router advertisements are received from the first andsecond internet protocol networks over the radio access network via thepacket data network connection.

In step S303, the router advertisements are passed to a host having anoperating system according to internet protocol networking principles.

According to an aspect of the invention, an apparatus for a secondinternet protocol network, such as the control unit 30, 40 shown in FIG.1, comprises means for logically connecting, to a packet data networkconnection provided between a user equipment and a first internetprotocol network over a radio access network, the second internetprotocol network located on a data path from the first internet protocolnetwork to the user equipment, wherein the first internet protocolnetwork represents the highest level internet protocol point ofattachment to the packet data network connection, and means for sendingrouter advertisements from the second internet protocol network to theuser equipment over the radio access network via the packet data networkconnection.

The means for logically connecting the second internet protocol networkto the packet data network connection may comprise a physical networkinterface located at the second internet protocol network and means forestablishing tunnels associated with bearer services.

The apparatus may further comprise means for mapping an access of thesecond internet protocol network within said packet data networkconnection to a dedicated bearer and means for routing routeradvertisements at the second internet protocol network to the dedicatedbearer.

The apparatus may further comprise means for providing the dedicatedbearer over a single radio link between the user equipment and the radioaccess network.

Alternatively or in addition, the apparatus may further comprise meansfor providing the dedicated bearer to the user equipment over multipleradio links between the user equipment and the radio access network.

The apparatus may further comprise means for associating n internetprotocol prefixes to the dedicated bearer, wherein n is an integer equalto or greater than zero.

The apparatus may further comprises means for setting a prefixadvertised by the second internet protocol network based on its levelinternet protocol point of attachment to the packet data networkconnection.

The apparatus may further comprise means for setting a common sharedprefix for each end host served by the second internet protocol network.

The above-described means may be implemented by the processing resources31, 41, memory resources 32, 42 and interfaces 33, 43 of the controlunits 30, 40, respectively.

According to an aspect of the invention, an apparatus of a firstinternet protocol network, such as the control unit 50, comprises meansfor establishing a packet data network connection between a userequipment and the first internet protocol network over a radio accessnetwork, means for mapping an access of the first internet protocolnetwork within said packet data network connection to a default bearer,means for routing router advertisements at the first internet protocolnetwork to the default bearer, and means for providing the defaultbearer associated with the first internet protocol network and adedicated bearer associated with each of second internet protocolnetworks logically connected to the packet data network connection, tothe user equipment.

The apparatus may comprise means for providing the default bearer over asingle radio link between the user equipment and the radio accessnetwork.

Alternatively or in addition, the apparatus may comprise means forproviding the default bearer to the user equipment over multiple radiolinks between the user equipment and the radio access network.

The first internet protocol network may provide its own internetprotocol prefix space.

The apparatus may comprise means for associating n internet protocolprefixes to the default bearer, wherein n is an integer equal to orgreater than zero.

The apparatus may further comprise means for setting a prefix advertisedby the first internet protocol network based on its level internetprotocol point of attachment to the packet data network connection.

The apparatus may further comprise means for setting a common sharedprefix for each end host served by the first internet protocol network.

The above-described means may be implemented by the processing resources51, memory resources 52 and interfaces 53 of the control unit 50.

According to an aspect of the invention, a user equipment such as thecontrol unit 20, comprises means for establishing a packet data networkconnection between the user equipment and a first internet protocolnetwork over a radio access network, means for receiving routeradvertisements from the first internet protocol network and secondinternet protocol networks over the radio access network via the packetdata network connection, wherein the first internet protocol networkrepresents the highest level internet protocol point of attachment tothe packet data network connection, and wherein the second internetprotocol networks are located on a data path from the first internetprotocol network to the user equipment and are logically connected tothe packet data network connection, and means for passing the routeradvertisements to a host having an operating system according tointernet protocol networking principles.

The above-described means may be implemented by the processing resources21, memory resources 22 and interfaces 23 of the control unit 20.

According to an aspect of the invention, a second internet protocolnetwork is logically connected to a packet data network connectionprovided between a user equipment and a first internet protocol networkover a radio access network, the second internet protocol networklocated on a data path from the first internet protocol network to theuser equipment. The first internet protocol network represents thehighest level internet protocol point of attachment to the packet datanetwork connection. Router advertisements are sent from the secondinternet protocol network to the user equipment over the radio accessnetwork via the packet data network connection.

It is to be understood that the above description is illustrative of theinvention and is not to be construed as limiting the invention. Variousmodifications and applications may occur to those skilled in the artwithout departing from the true spirit and scope of the invention asdefined by the appended claims.

1. A method for a second internet protocol network, the methodcomprising: logically connecting, to a packet data network connectionprovided between a user equipment and a first internet protocol networkover a radio access network, the second internet protocol networklocated on a data path from the first internet protocol network to theuser equipment, wherein the first internet protocol network representsthe highest level internet protocol point of attachment to the packetdata network connection; and sending router advertisements from thesecond internet protocol network to the user equipment over the radioaccess network via the packet data network connection.
 2. The method ofclaim 1, comprising: logically connecting the second internet protocolnetwork to the packet data network connection by means of a physicalnetwork interface located at the second internet protocol network andestablishing tunnels associated with bearer services.
 3. The method ofclaim 1, comprising: mapping an access of the second internet protocolnetwork within said packet data network connection to a dedicated bearerand routing router advertisements at the second internet protocolnetwork to the dedicated bearer.
 4. A method for a first internetprotocol network, the method comprising: establishing a packet datanetwork connection between a user equipment and the first internetprotocol network over a radio access network; mapping an access of thefirst internet protocol network within said packet data networkconnection to a default bearer; routing router advertisements at thefirst internet protocol network to the default bearer; and providing thedefault bearer associated with the first internet protocol network and adedicated bearer associated with each of second internet protocolnetworks logically connected to the packet data network connection, tothe user equipment.
 5. The method of claim 4, comprising: providing thedefault bearer and the dedicated bearer over a single radio link betweenthe user equipment and the radio access network.
 6. The method accordingto claim 4, comprising: providing the default bearer and the dedicatedbearer to the user equipment over multiple radio links between the userequipment and the radio access network.
 7. The method of claim 4,wherein the first/second internet protocol network provides its owninternet protocol prefix space.
 8. The method of claim 4, comprising:associating n internet protocol prefixes either to the dedicated beareror the default bearer, wherein n is an integer equal to or greater thanzero.
 9. The method of claim 4, comprising: setting a prefix advertisedby the first/second internet protocol network based on its levelinternet protocol point of attachment to the packet data networkconnection.
 10. The method of claim 4, comprising: setting a commonshared prefix for each end host served by the first/second internetprotocol network.
 11. A method for a user equipment, comprising:establishing a packet data network connection between the user equipmentand a first internet protocol network over a radio access network;receiving router advertisements from the first internet protocol networkand second internet protocol networks over the radio access network viathe packet data network connection, wherein the first internet protocolnetwork represents the highest level internet protocol point ofattachment to the packet data network connection, and wherein the secondinternet protocol networks are located on a data path from the firstinternet protocol network to the user equipment and are logicallyconnected to the packet data network connection; and passing the routeradvertisements to a host having an operating system according tointernet protocol networking principles.
 12. A computer program productincluding a program for a processing device, comprising software codeportions for performing the steps of claim 1 when the program is run onthe processing device.
 13. (canceled)
 14. (canceled)
 15. An apparatus ofa second internet protocol network, configured to: logically connect, toa packet data network connection provided between a user equipment and afirst internet protocol network over a radio access network, the secondinternet protocol network located on a data path from the first internetprotocol network to the user equipment, wherein the first internetprotocol network represents the highest level internet protocol point ofattachment to the packet data network connection; and send routeradvertisements from the second internet protocol network to the userequipment over the radio access network via the packet data networkconnection.
 16. The apparatus of claim 15, configured to: logicallyconnect the second internet protocol network to the packet data networkconnection by means of a physical network interface located at thesecond internet protocol network and establish tunnels associated withbearer services.
 17. The apparatus of claim 15, configured to: map anaccess of the second internet protocol network within said packet datanetwork connection to a dedicated bearer and route router advertisementsat the second internet protocol network to the dedicated bearer.
 18. Anapparatus of a first internet protocol network, configured to: establisha packet data network connection between a user equipment and the firstinternet protocol network over a radio access network; map an access ofthe first internet protocol network within said packet data networkconnection to a default bearer; route router advertisements at the firstinternet protocol network to the default bearer; and provide the defaultbearer associated with the first internet protocol network and adedicated bearer associated with each of second internet protocolnetworks logically connected to the packet data network connection, tothe user equipment.
 19. The apparatus of claim 15, configured to:provide the default bearer and the dedicated bearer over a single radiolink between the user equipment and the radio access network.
 20. Theapparatus according to claim 15, configured to: provide the defaultbearer/dedicated bearer to the user equipment over multiple radio linksbetween the user equipment and the radio access network.
 21. Theapparatus of claim 15, configured to: associate n internet protocolprefixes either to the dedicated bearer or the default bearer, wherein nis an integer equal to or greater than zero.
 22. (canceled) 23.(canceled)
 24. A user equipment, configured to: establish a packet datanetwork connection between the user equipment and a first internetprotocol network over a radio access network; receive routeradvertisements from the first internet protocol network and secondinternet protocol networks over the radio access network via the packetdata network connection, wherein the first internet protocol networkrepresents the highest level internet protocol point of attachment tothe packet data network connection, and wherein the second internetprotocol networks are located on a data path from the first internetprotocol network to the user equipment and are logically connected tothe packet data network connection; and pass the router advertisementsto a host having an operating system according to internet protocolnetworking principles.